Computer-controlled switching device

ABSTRACT

A computer-controlled switching device allows the control of such devices as contactors-breakers, protection switches of motors and the like. The computer is connected through an analog-digital converter to at least one current consumption monitoring detector and gives switching orders. The switching device is comprised of a unit module incorporating the detector(s) reacting to the magnetic field generated by the conductor(s) supplying the device to be controlled, the analog-digital converter(s), the computer comprised of a microprocessor, adjusting elements connected to the computer for introducing comparison values and other characteristic values, a cut-off element controlled by the output of the computer, with the relative connection terminals and, optionally, a power-supply unit. The module and its housing have passages for leads to the device to be monitored and detectors are mounted in their proximity.

The invention relates to a computer-controlling switching device forcontrolling power switching elements, such as relays, motor protectionswitches or the like, for controlling devices or installations whereinthe computer is connected through an analog-digital converter to atleast one detector monitoring the current consumption of the devicebeing monitored, for example a motor, transformer or the like, and emitsswitching signals when predetermined values are exceeded and/or are notreached.

Such a switching arrangement for switching devices of this type areknown from DE-AS (accepted German patent application) No. 2,310,103.

Furthermore, it has been proposed in DE-OS (laid-open German patentapplication) No. 2,641,677 to arrange all elements, that is power andcontrol part, of a three-phase drive for smaller to average power andvoltages on a printed circuit board.

It is the object of the invention to provide a switching device of thefirst-mentioned kind, which is easy to mount and which is distinguishedby a very simple mechanical structure.

This is achieved according to the invention by combining in a knownmanner the detector(s) responsive to the magnetic field of theconductor(s) leading to the device to be monitored, the analog-digitalconverter(s), the computer comprised of a microprocessor, the adjustingelements connected thereto for the input of comparison values andadditional characteristic data, as well as a switching elementcontrolled by the output of the computer, together with the associatedterminals and optionally a power-supply unit or a voltage source into aunit module, and this unit module as well as the housing thereof definespassages for the conductors leading to the device or the like to bemonitored and the detectors constituted, for example, by Hall generatorsare arranged in their proximity. The compact structure of the switchingdevice and the arrangement of passages for the conductors leading to thedevice to be monitored make a very simple assembly of the devicepossible. In practice, it is only necessary to disconnect the conductorsfrom the device to be protected or controlled or from the powerswitching element and to lead them through the switching device andre-connect them, the same as the control conductors leading to the powerswitching element.

In the case of the use of Hall generators as detectors in combinationwith the computer, the control device has the advantage that it isusable in a broad band width in relation to the magnitude of thecurrents to be monitored. Such a combination may readily attain, forexample, a current adjustment range of 1:10 in protection switches formotors.

A particularly simple mechanical structure of the switching deviceaccording to the invention results from a unit module consistingessentially of two prints electrically interconnected by detachable plugconnections, one of which is equipped with the switching elementcontrolled by the computer as well as optionally a power-supply unitand/or a voltage source and the other one is equipped with the detectorand the computer, together with the analog-digital converters and theadjusting elements. This substantially facilitates the design of theprints and, at the same time, the electronic structural parts operatingwith the lower voltages are separated from the structural parts usuallyoperating with higher voltages, such as a power-supply unit or theswitching element controlled by the computer, the latter, of course,only with respect to its output circuit. The arrangement of theelectronic structural parts operating only with lower voltages, forinstance 5 V, and those operating with a higher voltage, for instance220 V, such as power-supply unit and switching element, on separateprints avoids sources of trouble.

With respect to the manufacture and as low a cost as possible in theassembly of the switching device, it is particularly advantageous if ahousing is provided for the mechanical connection of the two prints,which is comprised of two halves which have passages or recesses forreceiving the terminals and the adjusting elements as well as passagescorresponding to the leads, and which may be interconnected--preferablyby a snap connection--and which have bosses on their interior surfaceswhich, in the assembled condition of the housing, press on the printedcircuit boards with their facing surfaces, the two prints beingpreferably interconnected with their facing conductive sides.

The invention will now be explained in more detail in conjunction withthe drawings wherein

FIGS. 1 and 2 show different embodiments of a switching device accordingto the invention;

FIG. 3 is an exploded view of the switching device of FIG. 1; and

FIGS. 4 and 5 are circuit diagrams for the operation of the switchingdevices according to FIGS. 1 and 2.

Switching device 1, 1' is a unit module equipped with adjusting elements2 for the setting or input of characteristic data, for example thenominal current of the motor to be monitored, in the computer as well asadditional, non-illustrated adjusting elements for setting additionalcharacteristic data, for example concerning starting conditions, ambienttemperature or the like. Further, reset button 3 is provided forresetting switching element 4 when the same responds in case ofmalfunction. Terminal block 5 carries terminals 6 for the connection ofthe coil of the power switching element to be controlled, terminals 7for a malfunction indicator and terminals 8 for the remote control ofthe resetting of switching element 4. In addition, light diodes 9 areprovided for indicating malfunctions. Passages 10 are provided for theconductors leading to the device to be monitored.

The embodiment of FIG. 2, which is provided additionally for the controlof star delta relays, also has another terminal block 11 with terminals12 for the connection of a thermodetector of the motor and terminals 13for the connection of the coils of the star delta relay. The structureof switching device 1 is shown in FIG. 3.

Adjusting elements 2, as well as additional, non-illustrated adjustingelements, are arranged in recesses 15 and 16 in housing half 17.Furthermore, printed circuit board 14 carries detectors 18 responsive tothe magnetic field generated by the conductors leading to the device tobe protected, which may be comprised, for example of Hall generatorscast into synthetic resin blocks defining passages for the conductors orof toroidal core converters, and the non-illustrated computer comprisedof a microprocessor, together with the associated analog-digitalconverters and the reset switch for resetting switching element 4 aswell as light diodes 9, together with the control circuit therefor forindicating a malfunction. Furthermore, brushings 19 are arranged onprint 14 for providing an electrical connection between prints 14 and20.

Printed circuit 20 is equipped essentially with terminal block 5,switching element 4 and power-supply unit 21 as well as pins fittinginto bushings 19 at the rear side thereof to provide an electricalconnection between the two printed circuits. Print 20 corresponds in itsdimensions to the section of print 14 free of detectors 18. The twoprinted circuits are mechanically held together, in addition to thefriction fit of the pins in bushings 19, by the two halves 17 and 22 ofthe housing which have passages 15, 16, 23, 24 and recess 25 and whichmay be assembled by a non-illustrated snap connection. Passages 15, 16,23 and recesses 24 are delimited by walls or shoulders which areinwardly directed and whose facing end surfaces define a gapwherebetween the two prints 14, 20 are clamped when the two housinghalves 17, 22 are interconnected.

FIG. 4 shows a circuit diagram for the operation of a switching deviceaccording to the invention, switching device 1 controlling relay 30 foractuating motor M and signal lamp 31.

According to the circuit diagram of FIG. 5, switching device 1' is alsocapable of controlling star delta relays 32, 33, the star relay beingcut off when the nominal current of the motor falls below apredetermined value, for example 90%, while the delta relay is switchedon only after the electric switching arcs of the star relay have beenextinguished and immediately after the motor currents have reached azero value, the value of the current being determined by the computer onthe basis of the data input and the determined operating parameters,such as, for example, duration, intensity as well as idle time beforethe start to be monitored.

Switching 1, 1' may usefully be supplied with current through conductorsL1 and L2 connected to terminals 6 and 7, which make it possible tosupply energy to the computer while M is idle and maintains switchingelement 4 which may be comprised of a semi-conductor structural part.Furthermore, however, a battery may be provided for supplying current toswitching device 1, 1' so that the determination of the operatingparameters is not interrupted in case of a power failure. This batterymay be charged constantly through the power-supply unit.

I claim:
 1. Computer-controlled switching device for controlling powerswitching elements for controlling devices wherein the computer isconnected through an analog-digital converter to at least one detectormonitoring the current consumption of the device being monitored, andemits switching signals when predetermined values are exceeded and/orare not reached, characterized in that the detector responsive to themagnetic field of the conductor leading to the device to be monitored,the analog-digital converter, the computer comprised of amicroprocessor, adjusting elements connected thereto for the input ofcomparison values and additional characteristic data, a switchingelement controlled by the output of the computer, and associatedterminals are combined into a unit module, this unit module as well as ahousing therefor defines passages for the conductors leading to thedevice to be monitored, and the detector is arranged in their proximity.2. Switching device according to claim 1, characterized in that the unitmodule is comprised essentially of two printed circuits which areelectrically connected by detachable plug connections and one of whichis equipped with the terminals and the switching element controlled bythe computer, and the other one is equipped with said detectors (18) andthe computer, together with the analog-digital converter and theadjusting elements.
 3. Switching device according to claim 1, furthercomprising a power-supply unit combined into the unit model. 4.Switching device according to claim 1, wherein the said detector isconstituted by a Hall generator.
 5. Computer-controlled switching devicefor controlling power switching elements controlling devices wherein thecomputer is connected through an analog-digital converter to at leastone detector monitoring the current consumption of the device beingmonitored, and emits switching signals when predetermined values areexceeded and/or are not reached, characterized in that the detectorresponsive to the magnetic field of the conductors leading to the deviceto be monitored, the analog-digital converter, the computer comprised ofa microprocessor, adjusting elements connected thereto for the input ofcomparison values and additional characteristic data, a switchingelement controlled by the output of the computer, and associatedterminals are combined into a unit module, the unit module is comprisedessentially of two printed circuits electrically connected by detachableplug connections, one of the printed circuits is equipped with theterminals and the switching element controlled by the output of thecomputer and the other printed circuit is equipped with said detectorand the computer, together with the analog-digital converter and theadjusting elements, said unit module and a housing therefor definespassages for the conductors leading to the device to be monitored, andthe said detector is arranged in their proximity, the housing beingcomprised of two halves and arranged for mechanically connecting the twoprinted circuits, the housing having passages for receiving theterminals and the adjusting elements as well as passages correspondingto passages in the printed circuits, and the housing halves areconnectable and have bosses at the inner surfaces thereof, the bossespressing on the printed circuits with their facing surfaces in theassembled condition of the housing.
 6. Switching device according toclaim 5, characterized in that the two printed circuits areinterconnected with their facing conductive sides.
 7. Switching deviceaccording to claim 5, wherein the one printing circuit is also equippedwith a power-supply unit.
 8. Switching device according to claim 5,characterized in that the said detector is constituted by a Hallgenerator.
 9. Switching device according to claim 5, further comprisinga snap connection for connecting the housing halves.